Printing telegraph motor control



J. C. F RICKE PRINTING TELEGRAPH MOTOR CONTROL Filed June 25, 1951 Dec. 8, 1931.

INVENTOR JACKSON C. FRICKE BY WW ATTORNEY Patented Dec. 8, 1931 UNITED STATES PATENT OFFICE JACKSON 0. FRICKE, OF BROOKLYN, NEW YORK, ASSIGNOR TO INTERNATIONAL COM- MUNICATIONS LABORATORIES, INC., OF NEW YORK, N. Y., A CORPORATION OF NEW YORK PRINTING TELEGRAPH MOTOR CONTROL Application filed June 25,

This invention relates generally to printing telegraph exchange systems, and more particularly to such systems in which the subscribers lines are normally open to direct current and are closed when alternating current is applied to these lines at the central station.

One of the principal objects of this invention is to increase the operating range of' the printers at the interconnected central and subscribers stations by removing the alternating current relay, used to close the subscribers line to direct current, from the line while communication is being carried on.

Another object is to provide means for indicating to the central station operator that the subscribers station printer motor has been started,

The present invention is an improvement ufpon an invention disclosed in. a previous application, Serial No. 469,393, filed July 21, 1930 in the name of applicant. According to the invention disclosed in that application, an alternating current relay at the subscribers station is operated by alternating current applied to the subscribers line at the central station. The operation of this relay closes the line to direct current, and

a mechanical locking device actuated by the relay then maintains the line closed while communication is carried on.

It has been found that the'alternating current relay, which remains connected'to the line circuit during signal transmission, has a tendency to reduce the operating range of the connected printers, and that revertive signalling means are necessary to inform the central station operator that the subscribers station printer motor has started. In the absence of the last-mentioned means, the central station operator might frequently send messages to an unattended subscribers station printer that could not bestarted, due to some local circuit trouble, without any knowledge that such'messages had not been received.

Accordingly, one feature of this invention is the extension of the circuit for operating the alternating current relay, through a con- 1931. Serial No. 546,715,

tact of a motor control relay, whereby the former relay is removed from the subscribersline circuit as soon as the latter operates.

Another feature is the provision of a relay that is operated, When the subscribers printer motor has reached a certain speed, to close a shunt around the motor control relay, thus increasing the line current to cause the lighting of a supervisory lamp at the central station operators set to indicate that the subscribers station motor has started.

Referring now to the drawing, 0 designates the central station operators set, C the central station concentration board, and S- the subscribers station. Only the elements necessary to a clear understanding of the invention have been shown, but it is obvious thatv by adding similar elements to those illustrated it would be possible to construct a printing telegraph exchange system capable of handling any desired number of subscribers.

The subscribers station S is connected with the central station concentration board C by a line 1 that is closed to alternating current through a winding of alternating current relay 5 but is open to direct current by reason of the condenser 2 and the normally open contact A of switch 6. When the alternating current relay 5 is operated, the switch 6 is operated to close its contacts and thus close the line circuit 1 to direct current. In this closed line circuit is a slow-releasing motor control relay 4 whose functions are to-control the operation of the slow-operating restoring relay 3, to start and stop the printer motor 12, and to disconnect the alternating current relay 5 from the line circuit 1 while communication is being carried on. The restoring relay 3, which is operated only when the line circuit 1 is broken at the concentration board C, is adapted to restore the switch 6 to its normal position and thus reopen the subscribers line circuit 1 to direct current. Associated with the printer motor 12 1s a relay 13 which is operable, after. the printer motor has reached a certain speed, to form a shunt for the line circuit 1 through a resist ance 7 and around the high resistance of the motor control relay 4 and thus cause the lighting of a supervisory lamp at the central station, in a manner to be described hereinafter, to indicate that the printer motor 12 has started. To permit the subscribers station S to call the concentration board C, a calling key 14 is provided and this key, when operated, closes the line 1 to direct current to light a supervisory lamp at the board, as will be described in detail below.

At the concentration board C are disclosed jacks 15 and 16 which are individually associated by line 1 with the subscribers station S. Connected through the contacts of these jacks and variable resistance 20 to subscribers line 1 is a line relay 17 having both an operating and a locking winding. The circuits for energizing these windings are controlled b slow-releasing relay 18 which is connecte to grounded negative battery 19 and to the sleeve of jack 16. This relay releases more slowly than motor control relay 4 at the subscribers station S in order to permit restoring relay 3 to operate and open the line 1 to direct current before the release of relay 18 connects battery to the line 1. Controlled by the line relay 17; is a supervi: sory lamp 21 individual to the subscribers station S.

' (lo-operating with the jacks 15 and 16 is a cord circuit with a tip circuit 22 and a sleeve circuit 23 extending from the central operators set at O and terminating in a plug at the concentration board C. -At the operators set are alternator 26 and grounded positive battery 27 which are connected to the tip 22 of the cord circuit bythe operation of relay and are disconnected by the op eration of ring down relay 24. This latter relay also serves to" connect the operators printer to the tip of the cord circuit, to complete a circuit for operating supervisory lamp 32 and to prepare a locking circuit for relay 34. The operators printer is of the usual type and consists of line relay 29, transmitter and printer magnets 36 associated with a contact of the line relay. This line relay has a continuously energized biasing windin A and an operating winding B whose attery connection is controlled by relay 25. The printer has associated therewith a printer motor which is controlled manually by the key 33 and relay 34. At the operators printer set is a supervisory lamp 37,

- and in the same circuit is another supervisory' lamp 38 at the concentration board. These lamps are controlled jointly by relay 25 and key 40 which, in turn, controls relay 39.

The operation of the above-described structure, when a call is being extended from. a subscrihcrs station S to a central station printer operator 6, will now be described. The subscriber operates key 14 which closes a. circuit to operate and lock line relay 17.

The operating circuit may be traced from grounded negative battery 19, contact A of relay 18, winding of relay 17, tip contact of line jack 1.6, tip contact of supervisory jack 15, variable resistance 20, subscribers line 1, key 14, winding of restoring relay 3 to ground. The locking circuit may be traced from battery 19, contact B of relay 18, windingof relay 17, contact A of relay 17 to ground. The operation of line relay 17 closes a circuit for lighting supervisory lamp 21, which may be traced from grounded circuit 23, winding of relay 25 to ground.

The operation of relay 25 closes the circuit of the supervisory lamps 37 and 38, thus informing the printer operator of an incoming call and making the cord circuit busy at thev concentration board. The circuit for operating these lamps may be traced from grounded positive battery 28, contact C of relay 25, lamp 38, lamp 37, contact A of relay 39 and ground. The operation of relay 25 also connects grounded positive battery 28 in series with the line relay 29 and the transmitting contacts 30 through contact D oi relay 25. At its B contact relay 25 applies alternating current, superimposed on direct current, to the subscribers line circuit 1 over a circuit extending from grounded positive battery 27, alternator 26, contact B of relay 25, winding and contact A of relay 24, tip 22 of the cord circuit, tip of jack 16, tip of jack 15, variable resistance 20, subscribers line 1, condenser 2, contact A of restoring relay 3, contact C of motor control relay 4, winding of alternating current relay 5 to ground. The alternating current relay 5 operates over the circuit just traced and closes contacts A and B of the switch 6, thus shunting the condenser 2 and closing the line circuit 1 through contact A of switch 6. The subscribers line 1 is thus closed to direct current over a circuit from grounded positive battery 27 alternator 26, contact B of relay 25, winding and contact A of relay 24, tip 22, tip of jack 16, tip of jack 15, variable resistance 20, line 1, contact A of switch 6, winding of motor control relay 4, printer magnets 8, transmitter 9 to ground. Upon closure of this circuit, motor control relay 4, but not relay 24, operates, closing at its B contact an alternative circuit to ground which shunts the high resistance of the printer magnets 8, thus accelerating the operation of motor control relay 4. The operation of motor control relay 4 being thus accelerated, its A contact is opened in time to prevent the operation of restoring relay 3 over an obvious circuit which was closed by the operation of alternating current relay 5. At its C contact the motor control relay 4 opens the circuit for operating the alternating current relay 5, thus disconnecting this relay from the line circuit 1. The release of alternating current relay 5, however, does not open the contacts of switch 6, but these contacts remain closed until positively opened by the subsequent operation of restoring relay 3. At is D contact motor control relay 4 closes an obvious circuit for operating the printer motor 12 and also a circuit for preparing relay 13 for operation. This latter relay, however, does not operate until the printer motor 12 has reached a certain speedandwhen this occurs relay 13 operates to shunt the line circuit 1 around the high resistance of the motor control relay 4, thus increasing the current in the line circuit 1. Upon this increase in the line current, relay 24'operates over the circuit previously traced and locks through ground on the A contact of relay 25. Relay 24 opens its A and closes its B contact, thus cutting off the alternating current superimposed on direct current from line circuit 1 and closing this line circuit through the transmitting contacts and windings of line relay 29 to grounded positive battery 28. The operation of relay 24 also closes an obvious circuit for lighting a supervisory lamp 32. Upon seeing this supervisory lamp lighted, the central station operator is aware that the subscribers printer motor is running at the speed required for reception of signals and he, thereupon, operates key 33 to complete an obvious circuit for energizingrelay 34. The energization of this relay completes a. circuit for central station printer motor 35. The central station operator and'the subscribers station S are now interconnected. The alternating current relay 5 is removed from the line circuit and communication can now be carried on between the two stations.

When communication has ended, the central station printer operator operates key to energize relay 39 over an obvious circuit. The operation of this relay extinguishes lamps 37 and 3%. Upon perceiving extinguished lamp 38, the concentration board operator pulls down the plug from the jack 16, thus breaking the circuit through the printer motor control relay 4 and the relay l8, and tie-energizing sleeve relay 25. As the relay 18 releases more slowly than motor control relay 4, it is obvious that thecircuit from grounded battery 19 will not be closed through the line relay 1? and through printer motor control relay 4 until after the latter relay has released. The release of this relay motor control relay 4, contact B of switch 6,

winding of restoring relay 3 to ground. Relay 3 operates, re-opening contacts A and B and thus re-opening the line circuit 1 to direct current at Contact A and breaking at contact B the operating circuit of restoring relay 3. As the release of motor control relay 4 opened the circuit for operating the printer motor 12 and relay 3, the subscribers station is now restored to normal. At the central station operators set 0 the removal of the plug from the line jack 16 releases relay 25 which removes grounded battery 28 from line relay 29 and transmitter contacts 30 and .breaks the locking circuit for relay 24. Re-

lay 24 releases, reconnecting the winding of this relay to the tip of the plug circuit extinguishing lamp 32, and releasing relay 34 to stop the printer motor 35. All circuits at both the central and subscribers stations are thus restored to normal.

It is obvious from the above description that the operations when a call is initiated at the central station are'similar, and their description is therefore believed unnecessary.

What is claimed is:

1. In a printing telegraph exchange system, a first station, a second station, a line normally open to direct current connecting said stations, an alternating current relay connected in said line at said second station and responsive to alternating current applied to said line at said first station for closing said line to direct current, and means responsive to said closure for removing said alternating current relay from said line. 2. In a printing telegraph exchange system, a first station, a second station, a printer at said second station and a motor for driving said printer, a line normally open to direct current connecting said stations, means for closing said line to direct current, means responsive to said closure for starting said motor, and means operable when said motor has reached operating speed for causing an indication at the first station that said motor is running.

3. In a printing telegraph exchange system, a first station, a second station, a lamp at said first station, a printer, a motor for driving said printer and a relay associated'with said motor at said second station, a line normally open to direct current connecting said stations, means for closing said line to direct current, means responsive to said closure for starting said motor, means operable when said motor has reached operating speed for operating the relay associated therewith to increase the current in said line, and means at said first station responsive thereto for lighting said supervisory lamp.

4. In a printing telegraph exchange system, a second station, a line normally open to direct current connecting said stations, an alternating current relay connected in said line at said second station and responsive to alternating current applied to said line at said first station for closing said line to direct current, means responsive to said closure for removing said alternating current relay from said line and for conditioning said second station for communication with said first station, and means under control of said first station for reconnecting said relay to said In witness whereof, I hereunto subscribe my name this 23rd day of June, 1931.

" JACKSON C. FRICKE. 

